    import java.util.List;
import java.util.ArrayList;
import java.util.Random;
    public class CardDemo {
        public static final String[] SUITS = {"♠", "♥", "♣", "♦"};
        // 买一副牌
        private static List<Card> buyDeck() {
            List<Card> deck = new ArrayList<>(52);
            for (int i = 0; i < 4; i++) {
                for (int j = 1; j <= 13; j++) {
                    String suit = SUITS[i];
                    int rank = j;
                    Card card = new Card();
                    card.rank = rank;
                    card.suit = suit;
                    deck.add(card);
                }
            }
            return deck;
        }
        private static void swap(List<Card> deck, int i, int j) {
            Card t = deck.get(i);
            deck.set(i, deck.get(j));
            deck.set(j, t);
        }
        private static void shuffle(List<Card> deck) {
            Random random = new Random();
            for (int i = deck.size() - 1; i > 0; i--) {
                int r = random.nextInt(i);
                swap(deck, i, r);
            }
        }
        public static void main(String[] args) {
            List<Card> deck = buyDeck();
            System.out.println("刚买回来的牌:");
            System.out.println(deck);
            shuffle(deck);
            System.out.println("洗过的牌:");
            System.out.println(deck);
// 三个人，每个人轮流抓 5 张牌
            List<List<Card>> hands = new ArrayList<>();
            hands.add(new ArrayList<>());
            hands.add(new ArrayList<>());
            hands.add(new ArrayList<>());
            for (int i = 0; i < 5; i++) {
                for (int j = 0; j < 3; j++) {
                    hands.get(j).add(deck.remove(0));
                }
            }
            System.out.println("剩余的牌:");
            System.out.println(deck);
            System.out.println("A 手中的牌:");
            System.out.println(hands.get(0));
            System.out.println("B 手中的牌:");

            System.out.println(hands.get(1));
            System.out.println("C 手中的牌:");
            System.out.println(hands.get(2));
        }
    }

